Machine for injecting sand into core molds



July 15, 1958 R. E. ACKLEY $842,315

MACHINE FOR INJECTING SAND INTO CORE MOLDS Filed May 11, 1956 FIGZ INVENTOR. Elf/{APE [.fifklfl/ A T7'OPNEY MACHINE FOR INJECTING SAND CORE MoLDs Richard E. Ackley, Fond du Lac, Wis., assignor to Kickhaeter Qorporation, Cedar-burg, Wis., a corporation of Wisconsin Application May 11, 1956, Serial No. 584,206

Claims. (Cl. 22-

This invention relates generally to-an improvement in a machine for introducing casting sand into core molds, and mor specifically to improved discharge means for such a machine through whi h the casting sand isforced into the core molds.

Machines comprising essentially a hollow'body adapted to contain casting sand and having one or more discharge means through which the sand is forced into a core mold by pressure means such as. the introduction of compressed air into the hollow body are generally old in the art. Machines of this type are generallyreferred to in the industry as core shooters or core blowers. The prior art core blowers were normally provided with discharge means comprising either one or more small openings or orifices or openings 'providedwith rubber valve means. The use of the orifices as discharge-means is objectionable in that if the orifices are made of small enough diameter to prevent the casting sand from continuing to flow through the discharge means between successive core making operations, they then necessarily restrict the flow of the casting sand during a core making operation, that is when a core mold is being filled. A rubber valve means for use with the discharge means is objectionable because the valves wear quickly as a result of the abrasive action of the casting sand and soon become inefiective to prevent casting sand llow from the core blower through the discharge means during nonoperating periods. Applicants invention resides in an improved discharge means for a core blower that does not appreciably restrict the flow of casting sand to the mold during a core blowing operation and further positively limits the discharge of casting sand from the core blower between successive core blowing operations to the small quantity of casting sand contained within a portion of the discharge means.

It is therefore an object of the present invention to provide an improved discharge means for a core blower that will not unduly restrict the how of casting sand into the core mold during a core making operation.

Another object of the invention is to provide an improved discharge means for a core blower that effectively prevents the discharge of casting sand therethrough while the core blower is inoperative, that is between successive core making operations.

Still another object of the invention is the provision of discharge means for a core blower that reduces the core making time.

Objects and advantages other than those set forth above will be apparent from the following description when read in connection with the accompanying drawing, in which:

Fig. l is an elevation view in section of a core blower embodying the invention;

Fig. 2 is an enlarged fragmentary view in elevation of the discharge means of the core blower of Fig. 1;

Fig. 3 is a plan view of the structure of Fig. 2; and

Fig. 4 is a view taken along line 4-4 of Fig. 2.

States Patent O pressure tank 7 containing compressed air.

erally a casting sand storage'chamber 2 connected by a valve 3, air passage means 4 and valve 6 to a cylindrical The valve 3 is controlled by means of a servo motor 8 having a piston 9 disposed therein actuable by compressed air introduced into the motor 8 through an air passage 11 connected to an air compressor -(not shown). The valve 6 is controlled by means of a hand wheel 12 to regulate the amount of compressed air admitted to the sand storage chamber 2 and hence the rapidity with which the casting sand is injected into a core mold 13. The sand storage chamber 2 is provided with a head 14 at its lower end comprising a conical portion 16 connected to a perforated base plate 17 and forming an annular chamber 13 therewith. A bracket 19 fastened to the tank 7 carries-a piston 21' that supports a mold carrying plate 22 to which the core mold 13 is removably secured. The piston 21 is actuable by means of compressed air to urge the mold carrying plate 22 and core mold 13 against the head 14 of the sand chamber 2.

A part of the base plate 17 defined by the conical portion 16 of the sand chamber 2 is provided with appl-icants novel sand conducting discharge means comprising an inverted U-shaped hollow tube 23 having one leg 24. longer than the'other leg 26. The tube 23 is disposed with the leg 24 insertable in an opening 27 formed by the base plate 17 and rigidly secured thereto by Welding or any other suitable means. An intermediate portion'28 of the curved tube 23 is vertically disposed a greater distance from a horizontal plane containing the base plate 17 and opening 27 than the ends thereof. Thus, portion 28 is disposed farther from opening 2'? than the end of leg 26. As a result, when the sand in the chamber 2 is not subjected to pressure as when the core blower 1 is inoperative, the weight of the sand is insufficient to force sand upwardly through the leg 26 and out of the opening 27. The only sand leakage that occurs is limited to the small volume of sand contained in the leg 24 of thetube 23.

in the operation of the core blowing machine 1, the chamber 2 is initially filled with casting sand and the core mold i3 is secured to the plate 22 and positioned in register with the discharge means of the chamber 2. The valve 6 is opened by means of the hand wheel 12 a predetermined amount depending upon the volume of sand and the rapidity with which the sand is to be injected into the mold 13. To initiate the core making operation, compressed air is introduced through the passage 11 to the piston 9 of the servo motor 8 to urge the piston 9 upwardly causing the valve 3 to open. Compressed air in the pressure tank 7 passes through the valves 3, 6 and into the chamber 2 subjecting the sand therein to a high value of pressure forcing the sand through the tube 23 into the core mold 153. Excess air from the core mold i3 escapes through a wire screen 29 and perforations 31 in the plate 17 and passes into the chamber 18 and is then discharged to atmosphere through the peripheral perforations 32. Upon completion of the core making operation, the core mold 13 is removed. While the core blower 1 is inoperative, that is when the valve 3 is closed so that the sand in the chamber 2 is not subjected to any pressure, the only sand that is discharged from the chamber 2 is the sand contained in the longer leg 24 of the discharge means.

Although but one embodiment has been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

It is claimed and desired to secure by Letters Patent:

1. In a core blowing machine, the combination of: a pressure source, a sand chamber having an inlet opening disposed at the upper end thereof and having an outlet opening disposed at the bottom end thereof, means disposed adjacent said inlet opening for controlling the admission of pressure from said pressure source to said sand chamber, and an inverted substantially U-shaped tube disposed within said sand chamber and having one leg connected to said outlet opening, and having a second leg of shorter length than said one leg.

2. In a core blowing machine, the combination of: a pressure source, a sand chamber having an inlet opening disposed at the upper end thereof and having an outlet opening disposed at the bottom end thereof, means disposed adjacent said inlet opening for controlling the ad mission of pressure from said pressure source to said sand chamber, and an inverted substantially U-shaped tube disposed within said sand chamber and having a first leg connected to said outlet opening and a second leg of shorter length than said first leg, the legs of said U- shaped tube being substantially vertically disposed.

3. In a core blowing machine, the combination of: a pressure source, a sand chamber having an inlet opening disposed at the upper end thereof and having an outlet opening disposed at the bottom end thereof, means disposed adjacent said inlet opening for controlling the admission of pressure from said pressure source to said sand chambe, and an inverted substantially U-shaped tube disposed within said sand chamber and having a first leg disposed in registry with said outlet opening and rigidly secured to said sand chamber and having a second leg of shorter length than said first leg, the legs of said U-shaped tube being substantially vertically disposed.

4. In a core blowing machine, the combination of: a pressure source, a sand chamber having an inlet opening disposed at the upper end thereof and having an outlet opening disposed at the bottom end thereof, means disposed adjacent said inlet opening for controlling the ad mission of pressure from said pressure source to said sand chamber, and an inverted substantially U-shaped tube disposed within said sand chamber and having a first leg connected to said outlet opening and a second leg of shorter length than said first leg, the portion of said U-shaped tube intermediate said legs being vertically disposed a greater distance from the outlet opening than the end of said second leg.

5. In a core blowing machine having a sand chamber with an outlet opening at the bottom thereof through which sand is discharged by fluid pressure thereon into a chamber, a sand conducting tube secured tosaid outict opening and extending upwardly therefrom in said sand chamber, said tube having a reverse bend therein to provide a trap preventing the gravity escape of sand therethrough and being open at all times from end to end to provide for free passage of sand therethrough when lluid pressure is applied to the sand in said chamber.

References Cited in the file of this patent UNITED STATES PATENTS 524,783 Middleton Aug. 21, 1894 2,611,938 Hansberg Sept. 30, 1952 2,759,229 M-agnuson et al Aug. 21, 1956 FOREIGN PATENTS 732,747 Great Britain June 29, 1955 549,630 Germany Apr. 29, 19 

